Chromatography cabinet



1966 D. L. BRODSKY 3,265,214

CHROMATOGRAPHY CABINET Filed April 15, 1963 2 Sheets-Sheet 2 66' 24 In wanton ,David L.B7"0d57i:y;

United States Patent 3,265,214 (IHRUMATUGRAPHY CABINET David L. Brodslry, Providence, RI, assignor to Esco Products, llnc., Providence, RI, a corporation of Rhode Island Filed Apr. 15, 1963, Ser. No. 272,950 11 Claims. (Cl. 21019$) The present invention relates to apparatus for use in paper chromatography. More particularly, the present invention relates to a chromatography cabinet that is molded of an inert plastic material in a one-piece construction and that is integrally formed with self-contained pockets for retaining solution troughs in substantially true horizontal position.

Paper chromatography has been developed for the purpose of detecting the presence of an unknown material by the application of a sample solution on a limited area of a piece of filter paper. By using chromatographic techniques, the constituents of a complex mixture or a minor impurity may be determined in a relatively short period of time. Such results by the use of conventional analytical methods normally require exacting procedures that might take weeks to carry out. Chromatographic process reduces such exacting procedures to a simple process in which a small amount of the sample solution is placed on a limited area of a piece of filter paper. After the filter paper is exposed to a solvent and after a predetermined period of time has elapsed, the material will have migrated by capillary action from its point of application to some point along the length of the filter paper. If the sample solution is a mixture, it will have separated wholly or partially into its components, and by the utilization of known techniques and processes, these components may be identified and measured.

In order to carry out the chromatographic process, prior to the instant invention various types of cabinets and jars have been utilized together with associated equipment for locating the chromatography paper and solutions therein. Usually these prior known chromatography cabinets have consisted of a steel enclosure that may have some form of a lining therein and in which a removable rack of some form is placed. The removable rack in these prior known constructions was normally provided with brackets for receiving the solution troughs and the antisiphon rods that are. employed in the process. In all of the prior known constructions, the cabinets were formed with an outer shell, an inner lining, and a rack or bracket of some form. Glass units have also been employed in the chromatographic process, but such units also require the use of removable racks having brackets mounted thereon for receiving the solution carrying troughs.

The present invention resides primarily in the construction of a molded cabinet for use in paper chromatography wherein the heretofore known removable supports and brackets for the solution troughs are eliminated. The chromatographic cabinet of the present invention is preferably molded from an inert plastic material, such as Fiberglas, and further contains a chemically resistant resin that cooperates with the Fiberglas to resist chemical attack of the solvent that is located in the troughs and the vapor of which saturates the interior atmosphere of the cabinet. The basic unit that defines the cabinet is molded in a one-piece construction of the Fiberglas plastic material, the interior walls thereof being integrally formed with pockets for receiving the solvent troughs therein. Additional recesses are also molded in the cabinet walls for receiving the antisiphon rods that are associated with the solvent troughs and over which the paper used in the chromatographic process is suspended. By molding the cabinet of the present invention "ice in the manner as indicated, the usual support stand and associated brackets are eliminated. The cabinet of the present invention is also light in weight thereby providing for greatest convenience and ease of handling, and since the interior surfaces of the walls thereof are chemically resistant, control of the atmosphere and temperature within the cabinet is greatly facilitated. The integral molding of the trough receiving pockets and rod receiving recesses eliminates the support stands and brackets, and thus all metal parts are avoided, thereby resulting in reduced breakage of the equipment associated with the cabinet. Furthermore, by forming the cabinet of the molded plastic material, all of the pockets and recesses integrally molded into the walls of the cabinet may be positively located so that the troughs and rods received therein are properly oriented in level position with respect to the bottom of the cabinet. Thus, when the cabinet is properly leveled, the troughs and rods are necessarily disposed in level position. The cabinet of the present invention is further formed with other details of construction, such as a bottom drain and easily removable door for gaining access to an interior tray, that promote ease of handling of the cabinet and insure the greatest convenience in carrying out the paper chromatographic process.

It is therefore an object of the present invention to provide a cabinet for use in paper chromatography that is molded of a plastic material, thereby providing for greatest convenience and ease of handling thereof.

Another object of the invention is to provide a molded cabinet for use in paper chromatography wherein pockets and recesses are formed integrally with the side walls of the cabinet for receiving solvent troughs and antisiphon rods therein, the integral molding of the troughs and recesses eliminating the need for support stands and brackets and thereby eliminating the requirements for metal parts in the cabinet.

Still another object is to provide a molded plastic cabinet for use in paper chromatography wherein control of atmosphere and temperature within the cabinet is greatly facilitated by the use of chemically resistant resins in the plastic material from which the cabinet is molded.

Still another object is to provide a cabinet for use in paper chromatography wherein the bottom wall thereof is formed with a compound inclination to cause solvent dripping onto the bottom wall to be directed to a corner from which it is drained.

Still another object is to provide a tray that is mounted on supports located in a paper chromatographic cabinet that is easily removed from the cabinet through an opening therein.

Other objects, features and advantages of the invention will become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

FIG. 1 is a front elevational view with parts shown in section of the chromatographic cabinet embodied in the present invention; and

FIG. 2 is a side elevational view with parts shown in section of the cabinet illustrated in FIG. 1.

Referring now to the drawings, the chromatographic cabinet embodied in the present invention is generally indicated at 10 and as shown includes a housing 12 and a pivotally mounted lid generally indicated at 14. The housing 12 is molded in a one-piece construction of a plastic material, such as Fiberglas, and further includes a chemically resistant resin therein that insures that the interior surfaces of the cabinet walls will be impervious to the solvent employed in the paper chromatographic process. The use of the inert plastic material such as Fiberglas further enables the cabinet walls to be conveniently cleaned after each analysis, and it is understood that the use of Fiberglas or the like produces sufiicient structural strength for the cabinet to enable the cabinet to be handled without fear of damage thereto.

The housing 12 that is molded in a one-piece construction includes a front wall 16, a rear wall 18, side walls 20 and 22, and a bottom wall 24. The front and rear walls 16 and 18 that are located in opposed relation are integrally joined to the bottom wall 24 and to the side Walls 20 and 22. As seen in FIG. 2, the front and rear walls 16, 18 extend upwardly from the bottom wall 24 and terminate at the uppermost end thereof in a flange 26. It will be further noted in FIG. 2 that the inside surfaces of the front and rear walls are unobstructed and define a generally flat surface that extends from the bottom wall to the uppermost end of the housing.

Referring again to FIG. 1, the sidewalls 20 and 22 are more clearly illustrated therein, and as shown the side walls extend upwardly from the bottom wall 24 in opposed parallel relation. Joined integrally to the side walls 20, 22 adjacent the uppermost ends thereof are a plurality of spaced pockets 28, which, as shown in FIG. 2, are generally concave in configuration and are separated by shelf-like portions 30. The pockets 28 in each of the side walls are horizontally spaced with respect to each other and are further horizontally and vertically aligned with respect to a pocket located in the opposed side wall. As will be described hereinafter, each pair of aligned pockets 28 are adapted to receive a solvent trough indicated at 32 therein, the aligning of the pockets providing for the location of the troughs in substantially true horizontal relation when the housing is leveled. Since the pockets 28 are in effect carved out of the side walls 16 and 18, a protuberance indicated at 34 in FIG. 1 is formed on the outer surface of each of the side walls 20, 22. These protuberances 34 appear in spaced relation on the outer surfaces of the side walls and are generally curved in conformity to the pocket configuration and thereby adding to the ornamental appearance of the cabinet housing.

Formed integral with the rear surface of the pockets 28 and defining an extension thereof on the inner surfaces of the side walls 20, 22, is a shelf 36 that is disposed in stepped vertical relation with respect to the pockets 28. As seen more clearly in FIG. 2, a plurality of grooves or recesses 38 are formed in the shelf 36, each pair of the recesses 38 being associated with a pocket 28 and disposed generally over the edges of the pockets. The recesses 38 are also concave in configuration for receiving antisiphon rods 40 therein. The recesses 38 that are located in the shelves 36 of each side wall are also vertically and horizontally aligned so that when the rods 40 are located in position they are substantially disposed in true horizontal relation. As mentioned hereinabove, each of the pockets 28 is associated with a pair of the recesses 38 so that when the rods 40 are disposed in the assembled position thereof they are mounted directly above the outermost edges of the trough 32 that is received within the associated pockets 28. 7

Referring again to FIG. 1, it will be noted that the uppermost end of the side walls 20, 22 that are joined to the shelves 36 are offset with respect to the inside surfaces of the main portion of the side walls and further define the inner edges of the flange 26 to which the side walls are also joined.

In carrying out the paper chromatography process, it is necessary to saturate the atmosphere within the cabinet with a solvent vapor, and in order to seal the housing 12 to prevent leakage of the solvent vapor therefrom, the lid 14 is provided. The lid 14 may also be molded of a plastic material, such as Fiberglas, and has a generally square configuration that conforms to the flange 26 that is joined to the upper edges of the housing walls. In the form of the invention as illustrated herein, the lid 14 is hingedly secured to the housing 12 by a hinge 42 that is joined to the rear edge of the flange 26 and the adjacent rear edge of the lid 14. The lid 14 cooperates with a neoprene sponge gasket 44 that is disposed in a groove formed in the upper surface of the flange 26 to effectively seal the interior of the housing 12 when the lid is in the closed position thereof. Under normal circumstances, the weight of the lid 14 bearing against the neoprene seal 44 will effectively seal the interior of the housing 12. However, it is also contemplated to provide means for clamping the lid 14 in the closed position thereof to insure an air-tight seal between the lid and the housing. For this purpose, clamps indicated at 46 are provided and are secured to the underside of the flange 26 in pivotal relation and are thus adapted to move in overlying relation with respect to the lid 14 to effectively clamp the lid in the sealed position thereof. As shown in FIGS. 1 and 2, the clamps 46 are secured to the flange 26 adjacent the side walls 20, 22 and the front wall 16.

Since a contaminating solvent is sometimes employed in the chromatographic process, the vapors associated therewith can be very deleterious to the operator of the unit. In order to protect the operator from injury due to the vapors emanating from the interior of the cabinet, the lid 14 is provided with a plurality of refill holes 48 therein. Each of the holes 48 is disposed directly above a trough 32 so that the solvent to be used in a particular investigation may be introduced into the troughs by means of the filling holes 48. Suitable plugs 50 are normally placed in the refill holes 48 to enclose the openings 48 and effectively seal the lid during the chromatographic process. It is understood that the plugs 50 may be conveniently removed from the refill holes 48 whenever the troughs 32 are to be refilled with a solvent material.

It is sometimes desirable during a particular process to observe the reaction of the solvent on the chromatographic paper and the movement of the various components of the solution that has been added to the paper. For this purpose, an insulating window 52 is positioned in the lid 14 and overlooks the antisiphon rods over which the chromatographic paper is suspended. Additional windows may also be located in the housing walls, and, as illustrated in FIG. 2, a relatively large window 54 also formed of insulated glass is provided for observing the chromatographic paper suspended from the rods 40 during any time that a particular process is being carried out.

Since the cabinet housing is normally saturated with the solvent vapors, and furthermore, since the paper used for carrying out the chromatographic process is saturated with the solvent solution, there is a tendency for the solvent to accumulate on the bottom wall 24 within the housing 12. In order to prevent this accumulation of the solvent on the bottom wall 24, a tray 56 is provided and is mounted on spaced supports 58 and 60 that are located on the inner surface of the bottom wall 24. As shown in the drawings, the tray 56 is formed with inclined walls that extend outwardly into engagement with the Walls of the housing 54. The inclined formation of the tray walls tends to inhibit flow of solvent onto the bottom wall 24 and thus provides for trapping of the majority of the solvent accumulating at the bottom of the housing within the tray 56. The tray 56 may be conveniently removed from within the housing 12 through an opening 60 located in the front wall 16 adjacent the lower end thereof. A door 62 is conveniently mounted in the opening 60 for enclosing the tray 56 within the housing 12. Any suitable means may be provided for locking the door 62 in position, it being understood that the interior of the housing 12 must not be exposed to any metal parts that might be contaminated.

Although the tray 56 is designed to catch the accumulated solvent that has condensed from the vapors circulating within the housing 12, some of the solvent does seep between the tray and the housing walls. In order to drain the accumulation of the solvent on the bottom wall 24, the bottom wall is provided with a compound inclination. The compound inclination of the bottom wall 24 is more clearly shown in FIGS. 1 and 2 wherein the wall is shown sloping toward the front wall 16 and also toward the side wall 20. By providing the compound inclination of the bottom wall 24, the accumulated solvent will be directed to a corner of the bottom wall 24, from where the solvent is drained through a drain port 64. It is understood that the drain port 64 communicates with a suitable opening formed in the corner of the bottom wall to which the accumulated solvent is drained.

In carrying out the process of paper chromatography, it is essential that the cabinet be maintained in a level position since the penetration of the sample solution on the paper is vitally affected by the position of the troughs 32 and the antisiphon rods 40. In order to properly level the cabinet, suitable leveling jacks 66 are provided and are secured to the underside of the bottom wall 24. The jacks 66 may be adjusted in any convenient fashion and are normally provided with a threaded portion that threadably engages an opening in the bottom wall 24.

In use of the cabinet in carrying out the paper chromatographic process, the troughs 32 are placed within the opposed pockets 28 that are formed in the side walls 20, 22 of the housing 12. The troughs 32 have a generally curved configuration that corresponds to the concave shape of the pockets 28 and thus nest within the pockets 28 as illustrated in FIG. 2. The antisiphon rods 40 are also placed in position within the housing 12 and are received within opposed recesses 38 as indicated in FIG. 2. A

pair of the antisiphon rods are associated with each trough 32 and are disposed generally above the edges of the trough 32. After the troughs have been filled with a suitable solvent solution, paper normally employed in the chromatographic process is then placed in position by =10- cating one edge of the paper in the trough 32 and immersed in the solution therein. The paper is retained in position within the trough 32 by an anchor rod 68. The paper is suspended over one of the antisiphon rods 40 and is allowed to drape downwardly within the housing 12 as indicated in the drawings. If desired, a second paper may be used in connection with each trough and suspended over the other adjacent antisiphon rod 40. It is understood, of course, that in carrying out the process, a plurality of paper samples will be suspended in position over the antisiphon rods, their ends being retained within the solution located in a trough 32. In all cases, the anchor rods 68 are utilized to locate the paper in proper position. As indicated in FIGS. 1 and 2, only one sample of paper indicated at 70 is shown suspended over an associated antisiphon rod 40.

As has been hereinbefore set forth, it is essential in carrying out the paper chromatographic process in the required manner that the filter paper 70 be located in substantially level position, and hence it is equally essential that the troughs 32 and antisiphon rods 40 also be level, since the position of the paper is obviously de-- pendent on the position of the troughs and antisiphon rods. By forming the cabinet with the integral pockets 28 and recesses 38, the location of the troughs and rods in the level position thereof is insured when the cabinet 14 is leveled by the leveling jacks 66. If the troughs were not in level position, the solvent would unevenly penetrate along the length of the paper, resulting in incorrect and inaccurate results.

In carrying out the process, a small amount of sample solution is placed on a limited area of the filter paper 70 which is then irrigated with the solvent solution located within the trough 32. The sample solution is normally placed on the paper at the crease just above the antisiphon rod 40 and is thus carried with the solvent solution by capillary action down the length of the paper 70.

Since the different components of the sample solution will move downwardly on the paper for different distances, depending upon the characteristics thereof, these differences and locations of the components of the sample solutions are utilized to identify them and to estimate their quantities.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.

What is claimed is:

1. In apparatus for use in paper chromatography, a cabinet molded in a one-piece construction of an inert plastic material that is combined with a chemically resistant resin, and cabinet including integrally formed front, rear, side and bottom walls, the interior surface of each of said side walls having a plurality of spaced pockets formed therein, each pocket in one side wall being aligned with a corresponding opposed pocket formed in the other side wall, a shelf formed on each side wall in stepped vertical relation with respect to the spaced pockets formed therein, a plurality of grooves formed in each shelf in horizontal spaced relation, each groove in one shelf being aligned with a corresponding groove formed in the other shelf, a plurality of troughs extending across the interior of said cabinet in parallel relation, each of said troughs being received in oppositely located pockets and being adapted to receive a solvent therein, an anchor rod located in each trough for anchoring a sample of paper therein, a plurality of anti-siphon rods extending across the interior of said cabinet in parallel relation and being received in oppositely located grooves, and a lid located on the uppermost end of said cabinet for sealing the interior thereof.

2. In apparatus as set forth in claim 1, said bottom wall having a compound inclination for directing into a corner thereof the solvent that has dripped from the paper onto the bottom wall, and a drain located at said corner for draining the solvent that has accumulated thereat.

3. In apparatus as set forth in claim 1, at least two supports located on said bottom wall in spaced relation, a tray mounted on said supports and including inclined side walls that are located in close proximity to the walls of said cabinet and being adapted to prevent substantial dripping of the solvent onto the bottom wall of said cabinet.

4. In apparatus as set forth in claim 1, the pockets formed in one side wall being in vertical alignment with the pockets formed in the other side Wall so that the troughs located the-rein are disposed in horizontal relation when said cabinet is in level position.

5. In apparatus for use in paper chromatography, a cabinet molded in a one-piece construction and having substantially integral, vertically extending walls, the interior surfaces of two of said walls that are located in opposed relation being formed with a plurality of concave pockets adjacent the upper ends thereof, said pockets being located in horizontal spaced-apart relation and a pocket in one wall being vertically aligned with a pocket on the opposed wall to retain a trough therein in substantially true horizontal relation when said cabinet is level, and a shelf formed in each of said opposed walls vertically above said pockets and having a plurality of recesses formed therein, a pair of said recesses being located in close proximity to a pocket and being associated therewith, each recess being horizontally and vertically aligned with a recess in the opposed shelf for receiving an elongated rod over which chromatographic paper is suspended.

6. In apparatus for use in paper chromatography, a cabinet molded in a one-piece construction and including a plurality of walls, at least two of which are located in opposed relation, the interior surface of said opposed walls being formed with a plurality of concave pockets that are disposed in horizontal spaced-apart relation, each pocket in one wall being aligned with a corresponding opposed Pocket in the other wall, each pair of opposed pockets receiving a trough therein for locating said trough in substantially true horizontal relation when said cabinet is in level position, and a lid located on the uppermost end of said cabinet for sealing the interior thereof.

7. In apparatus as set forth in claim 6, a stepped horizontally extending shelf located vertically above each of said opposed walls, a plurality of spaced-apart recesses formed in each of said horizontally extending shelves, the recesses in one shelf being vertically and horizontally aligned with the recesses in the other shelf for receiving rods in horizontal relation therein over which chromatographic paper is suspended.

8. In apparatus as set forth in claim 6, said cabinet including a bottom wall that has a compound inclination, said trough having a solution therein for impregnating a sample paper that communicates with the interior of said trough, said inclined bottom wall directing solution dripping from said paper or trough or condensing from solvent vapors in said cabinet into a corner of said cabinet, and a drain located at said corner for draining accumulated solvent therefrom.

9. In apparatus as set forth in claim 8, supports located on said bottom wall interiorly of said cabinet and in spaced relation, a tray mounted on said supports and having inclined side walls that are positioned in close proximity to the walls of said cabinet, for preventing substantial dripping of the solvent onto the bottom wall of said cabinet.

10. In apparatus as set forth in claim 9, an opening formed in a wall of said cabinet, adjacent the lower end thereof and providing for removal of said tray therethrough, and a door removably mounted in said opening for enclosing said cabinet at the lower end thereof when said cabinet is in use.

11. In apparatus for use in paper chromatography, a cabinet molded of an inert plastic material in a one-piece construction, said cabinet being formed with opposed walls and a bottom wall and having a lid located on the uppermost end thereof to define an enclosure, two of said opposed walls being preformed with a plurality of horizontally spaced pockets, the pockets in one wall being horizontally and vertically aligned with respect to the pockets in the opposed wall, each pair of opposed pockets being adapted to receive a solution carrying trough therein and locating said trough in substantially true horizontal relation when said cabinet is in level position.

References Cited by the Examiner UNITED STATES PATENTS 3,018,000 1/1962 Kopp 210-348 X 3,214,024 10/1965 Shandon 210198 REUBEN FRIEDMAN, Primary Examiner.

S. ZAHARNA, Assistant Examiner. 

1. IN APPARATUS FOR USE IN PAPER CHROMATOGRAPHY, A CABINET MOLDED IN A ONE-PIECE CONSTRUCTION OF AN INERT PLASTIC MATERIAL THAT IS COMBINED WITH A CHEMICALLY RESISTANT RESIN, AND CABINET INCLUDING INTEGRALLY FORMED FRONT, REAR, SIDE AND BOTTOM WALLS, THE INTERIOR SURFACE OF EACH OF SAID SIDE WALLS HAVING A PLURALITY OF SPACED POCKETS FORMED THEREIN, EACH POCKET IN ONE SIDE WALL BEING ALIGNED WITH A CORRESPONDING OPPOSED POCKET FORMED IN THE OTHER SIDE WALL, A SHELF FORMED ON EACH SIDE WALL IN STEPPED VERTICAL RELATION WITH RESPECT TO THE SPACED POCKETS FORMED THEREIN, A PLURALITY OF GROOVES FROMED IN EACH SHELF IN HORIZONTAL SPACED RELATION, EACH GROOVE IN ONE SHAFT BEING ALIGNED WITH A CORRESPONDING GROOVE FORMED IN THE OTHER SHELF, A PLURALITY OF TROUGHS EXTENDING ACROSS THE INTERIOR OF SAID CABINET IN PARALLEL RELATION, EACH OF SAID TROUGHS BEING RECEIVED IN OPPOSITELY LOCATED POCKETS AND BEING ADAPTED TO RECEIVE A SOLVENT THEREIN, AN ANCHOR ROD LOCATED IN EACH TROUGH FOR ANCHORING A SAMPLE OF PAPER THEREIN, A PLURALITY OF ANTI-SIPHON RODS EXTENDING ACROSS THE INTERIOR OF SAID CABINET IN PARALLEL RELATION AND BEING RECEIVED IN OPPOSITELY LOCATED GROOVES, AND A LID LOCATED ON THE UPPERMOST END OF SAID CABINET FOR SEALING THE INTERIOR THEREOF. 